EPA Finalizes TSCA Risk Evaluation for Solvent 1,1-Dichloroethane
EPA has determined that 1,1-dichloroethane presents an unreasonable risk of injury to human health in its final Toxic Substances Control Act (TSCA) risk evaluation for the chlorinated solvent, released June 20, 2025.
The agency identified worker risks from three specific conditions of use (COUs): processing for recycling, and processing as a reactant as an intermediate in certain chemical and chemical product manufacturing. Five other evaluated COUs did not significantly contribute to the risk determination, and the agency did not identify unreasonable risks to the general public or the environment.
The evaluation found that exposure to 1,1-dichloroethane may increase the risk of non-cancer renal, olfactory, and reproductive effects, as well as tumor formation, based on hazard read-across data from 1,2-dichloroethane, an isomer of the solvent.
Because EPA determined that 1,1-dichloroethane presents an unreasonable risk, the agency is statutorily required to issue a final rule that mitigates those risks within two years, with up to two years of extensions possible.
Narrowed Findings
Notably, the final risk evaluation reached significantly less conservative conclusions about 1,1-dichloroethane’s risks than the draft risk evaluation, released in July 2024. The draft found that seven COUs significantly contributed to the determination instead of three, and identified unreasonable risks to the environment based on risks to algae and invertebrates.
Among the changes made in the final risk evaluation were revisions to the “considerations of risk factors” for repackaging and disposal, use of “central tendency instead of the high-end for dermal exposure” for all COUs, and the incorporation of “considerations of personal protective equipment (PPE) use.”
According to EPA, 1,1-dichloroethane is primarily used to produce other chlorinated solvents with “broad industrial applications.” The final risk evaluation notes that, in 2020, between 200 million and one billion pounds were manufactured by two corporations in the Southern US, with none imported.
More information on the risk evaluation can be found on EPA’s website.
